Boas enhanced heat transfer surface

Abstract

A seal assembly includes a seal arc segment that defines first and second seal supports and radially inner and outer sides with the radially outer side including radially-extending sidewalls and a radially inner surface that joins the radially-extending sidewalls. The radially-extending sidewalls and the radially inner surface define a pocket. The seal assembly includes a carriage that defines first and second support members with the first support member supporting the seal arc segment in a first ramped interface and the second support member supporting the seal arc segment in a second ramped interface. The radially inner surface has a higher surface roughness than the radially extending sidewalls.

The invention claimed is: 
     
       1. A seal assembly comprising:
 a seal arc segment defining first and second seal supports and radially inner and outer sides, wherein the first seal support is circumferentially spaced from the second seal support with respect to the seal arc segment, the radially outer side including four contiguous radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket, the first seal support extending from a first of the radially-extending sidewalls, and the second seal support extending from a second of the radially extending sidewalls circumferentially opposite the first of the radially-extending sidewalls; 
 a carriage defining first and second circumferentially spaced support members, the first support member supporting the first seal support of the seal arc segment in a first ramped interface and the second support member supporting the second seal support of the seal arc segment in a second ramped interface, 
 wherein the radially inner surface has a higher surface roughness than the radially extending sidewalls. 
 
     
     
       2. The seal assembly as recited in  claim 1 , wherein the radially inner surface defines a plurality of channels. 
     
     
       3. The seal assembly as recited in  claim 2 , wherein the radially inner surface has a first section and a second section spaced axially from the first section, and the channels are deeper in the first section than in the second section. 
     
     
       4. The seal assembly as recited in  claim 2 , wherein the radially inner surface has a first section and a second section spaced axially from the first section, and the channels are spaced farther apart in the first section than in the second section. 
     
     
       5. The seal assembly as recited in  claim 2 , wherein the channels separate a plurality of fins. 
     
     
       6. The seal assembly as recited in  claim 2 , wherein the channels are circumferentially extending. 
     
     
       7. The seal assembly as recited in  claim 1 , wherein the seal arc segment comprises ceramic. 
     
     
       8. The seal assembly as recited in  claim 1 , wherein the radially inner surface has a first section and a second section spaced axially from the first section, and the surface roughness at the first section is different than the surface roughness of the second section. 
     
     
       9. The seal assembly as recited in  claim 2 , wherein the channels are round-bottomed channels. 
     
     
       10. A rotor assembly comprising:
 a rotor rotatable about an axis; 
 a seal arc segment radially outward of the rotor and defining first and second seal supports and radially inner and outer sides, wherein the first seal support is circumferentially spaced from the second seal support with respect to the seal arc segment, the radially outer side including four contiguous radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket, the first seal support extending from a first of the radially-extending sidewalls, and the second seal support extending from a second of the radially extending sidewalls circumferentially opposite the first of the radially-extending sidewalls; 
 a carriage defining first and second circumferentially spaced support members, the first support member supporting the first seal support of the seal arc segment in a first ramped interface and the second support member supporting the second seal support of the seal arc segment in a second ramped interface, 
 wherein the radially inner surface has a higher surface roughness than the radially extending sidewalls. 
 
     
     
       11. The rotor assembly as recited in  claim 10 , wherein the radially inner surface defines a plurality of peaks and valleys, and the peaks and valleys are arranged in a non-random pattern.